The transition to middle school can be a risky time for many adolescents, as youth are exposed to a host of new academic challenges and social relationships with older peers. Being placed foster care amplifies this risk. The purpose of this study is to conduct a randomized effectiveness trial to determine whether adding a preventive intervention at this critical transition period is effective and cost effective in terms of ameliorating outcomes such as drug and tobacco use, participation in HIV- risking sexual behavior, delinquency, mental health problems, and school failure for young adolescents in foster care. The proposed LINKS intervention marries the goals of child welfare and educational systems and will be implemented in the San Diego Unified School District which is the 2nd largest school district in California. LINKS, a 20-week, two pronged intervention that focuses on increasing parent and youth skills and support will be delivered by community-based paraprofessionals who will be trained and supervised to implement the intervention. An ongoing fidelity monitoring system will allow for the calibration of intervention staff performance to adherence standards, provide performance standards for local staff training, and build in monitoring for local support and oversight (i.e., at the system leadership level) in the school district and child welfare systems. The study is designed to maximize the potential for uptake, sustainability, and future scale-up to other school and child welfare systems given positive results from this effectiveness trial. The aims are: a) to determine the effectiveness of the LINKS intervention on key behavioral health and school adjustment outcomes, b) to examine mechanisms of action; specifically the mediating effects of placement failure on outcomes, c) to examine the moderating role of fidelity on outcomes, and d) to examine cost effectiveness and cost avoidance of LINKS. All eligible 5th graders enrolled in the San Diego Unified School District placed in foster or kinship care (and their caretakers) will be recruited over a 4-year period and will be assessed at baseline, and at 6, 12, and 18 month follow-ups. It is hypothesized that those participating in LINKS will experience fewer negative behavioral health outcomes and better school adjustment and that these effects will be mediated by higher levels of placement stability and moderated by intervention fidelity scores.